A keyboard is one of the input devices that are widely used in a computer system. For optimizing the operation experiences of the users, different types of keyboards are needed according to different input requirements. For example, the keyboard for inputting characters and commands uses a rubber dome as a means of elastically restoring the key structure after the key structure is depressed. However, the tactile feel of depressing the rubber dome is monotonous. In case that the keyboard is operated to play the computer game, the keyboard is unable to provide more clear tactile feedback. Consequently, a mechanical keyboard with mechanical key switches is often used to operate the function of the computer game.
Generally, a key structure of a conventional mechanical keyboard comprises a keycap, a sliding shaft, a spring, an upper fixing case, a lower fixing case, a fixing frame and a base plate. The sliding shaft is covered by the keycap. A bulge is protruded from a bottom end of the sliding shaft. A portion of the spring is sheathed around the bulge. When the upper fixing case and the lower fixing case are combined together, an accommodation space is defined between the upper fixing case and the lower fixing case. A side of the spring away from the sliding shaft is penetrated through the upper fixing case and the lower fixing case. Moreover, an end of the spring is protruded out of the lower fixing case. The lower fixing case is installed on the base plate. After the end of the spring is protruded out of the lower fixing case, the end of the spring is connected with the base plate. The fixing frame is arranged around the lower fixing case.
Since the key structure of the conventional mechanical keyboard is very complicated, the assembling structure and the assembling process of the key structure are very complicated. In other words, the assembling cost is high. Moreover, the key structure of the conventional mechanical keyboard cannot generate the feedback of a click sound. When the key structure of the mechanical keyboard is depressed, the user cannot recognize whether the key structure of the mechanical keyboard is really depressed. Moreover, since the key structure of the mechanical keyboard is complicated, the key structure occupies a lot of space. In other words, it is difficult to design a slim-type mechanical keyboard. Therefore, there is a need of providing an improved key structure of a mechanical keyboard in order to overcome the drawbacks of the conventional technologies.